Attachment for machine gun cradles



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ATTACHMENT FOR MACHINE GUN CRADLES Filed Jan. 18, 1940 5 Sheets-Sheet l JOHN c. Worm? Mb. llw H43, J. c. TROTTER ATTACHMENT FOR MACHINE GUN CRADLES s sheets-sheet 2 Filed Jan. 18, 1940 m .wm

Mh. 2,' WM. J. c. TRoT'n-:R

ATTACHMENT FOR MACHINE GUN GRADLES Filed Jan. 1a, 1940 3 sheets-sheet s atentos! Feb. 2, i943 PATENT GFF ll'ohn C. Trotter, Buffalo, N. Y., assignor to Bell Aircraft Corporation, Buifalo, N. Y., a corporation of New York Application January 18, 1940, Serial No. 314,542

(Cl. 'S9- 42) 4 Claims.

The present invention relates to machine guns and more particularly to a mounting means for machine guns for use in aircraft, Specifically, the mount is provided with a novel recoil dampening mechanism, buffer guard and safety lock for the firing triggers.

I am, of course, aware that devices have heretofore been provided for dampening the recoil of machine guns mounted in aircraft. However, the majority of these prior recoil constructions have materially increased the weight of the mount and in addition make it somewhat bulky and cumbersome.

An object of the present invention is to provide a mount for a machine gun that carries a recoil dampening device which is highly elficient and which consists of few working parts.

Another object of this invention is to provide a recoil dampener for machine gun mounts that will compensate for the recoil of the guns whether they are ring forwardly, upwardly or downwardly.

A still further object of this invention is to provide a recoil control mechanism for machine guns in which there is added dampening when L the guns are being fired at high angles above the horizontal.

Still a further object of this invention is to provide a buffer guard for a machine gun which can be moved to operative and inoperative positions with a maximum of ease and which will remain positively locked in its operative position.

A further object is to `provide a safety lock for the firing trigger which is simple in construction and operation and which is easily actuated by l the operator of the gun.

To accomplish the above and other important objects, the invention in general embraces the idea of providing a single recoil chamber suitably carried by the gun cradle and the forward portion of the gun. The recoil chamber is so constructed that it will adequately dampen the recoil when the gun is ilring in a substantially horizontal plane and yet have an added dampening when the gun is firing at a high angle, thus 1 taking care of the weight of the gun in addition to the recoil thereof.

Moreover, the cradle is provided with a novel buffer guard which can be easily moved from its operative to its inoperative position and which is held in its operative position by a spring pressed latch.

Additionally, a safety lock is slidably associated with the buffer guard for locking the firing trigger in its non-firing position and is so disposed that it can be easily manipulated by the operator of the gun.

The yoke for mounting the machine gun cradle in the fuselage of the airplane can be used to enable the gun to be fired at a 90 angle either above or below the horizontal.

In the drawings in which like numerals indicate the same or similar parts, a

Figure 1 is a side elevational view of my novel machine gun mount and its associated parts having the machine gun depicted in dot-dash lines.

Figure 2 is a top plan view of the assembly shown in Figure 1.

Figure 3 is a transverse sectional View taken on the line 3-3 of Figure 1 looking in the direction of the arrows.

Figure 4 is a horizontal sectional view taken on the line 4 4 of Figure 1 looking in the direction of the arrows.

Figure 5 is a sectional view taken along the line 5 5 of Figure 4 looking in the direction of the arrows.

Figure 6 is a longitudinal vertical sectional View of the recoil dampening cylinder and piston showing the parts in position when firing on or below the horizontal.

Figure '7 is a view similar to Figure 6 showing the parts when the gun is ring at an angle above the horizontal.

Figure 8 is a sectional view taken along the line 8--8 of Figure 6 looking in the direction oi' the arrows.

Figure 9 is a sectional view taken along the line 9-9 of Figure 6 looking in the direction oi the arrows.

Referring to Figure l, it will be seen that there is provided a cradle I supporting a machine gun 2. The cradle l comprises a pair of parallel longitudinally extending. members 3. A slide track 4 is attached to the rear extremities of each of the tubes 3 and is provided with an elongated slot 5. A bolt 6 carrying a sliding block l is mounted in the slot 5 and is attached at its inner end to the rear portion of the machine gun 2.

Secured to the rear end of each track 4 is a tubular member 8. The outer ends of each tubular member 8 are joined to a tubular member 9 which extends at right angles to the tubular members. Integrally formed with each end of the member 9 is an upstanding support lo over which ts a hand grip ll. The hand grips ll are employed by the operator ofi-the gun to regulate the direction in which the gun is fired. The grips ll consequently are a portion of the cradle l and are not attached to the gun itself.

Referring now to Figure 2, it will be noted that each tubular member 3 extends through an upstanding bracket I2. The brackets I2 are connected by means of the transversely extending member I3. A yoke I4 is pivotally connected at its upper ends as shown at I5 to the brackets I2 for permitting the cradle I to be moved in a vertical plane. The lower extremity of the yoke is formed with a spindle I6 which is fitted into a socket (not shown) in the fuselage of the airplane to permit the cradle to have swiveling movement. When the yoke is attached to the brackets in the Iposition shown in full lines in Figure 1, the gun may be rotated to rire upwardly to approximately a 90 angle. However, should it be desired to mount the gun to fire downwardly at this same angle, the position of the yoke I4 may be reversed to the position shown by dotdash lines. It will be appreciated by this very simple construction it is possible for the guns to have a greater flexibility of operation for firing upwardly or downwardly which is of course highly advantageous.

As shown in Figure 2, a recoil cylinder designated generally I1 is disposed between the parallel tubes 3 at the forward portion of the cradle I. The outer end of the cylinder I1 is formed with laterally extending members I8 carrying a cup I9 at ach end thereof. The-cup I9 fits over the open end of each tube 3. The cylinder I1 has a piston rod and an eyelet 2I is formed at the outer end of the rod. A bolt 22 is adapted to extend through the eyelet and through apertures formed in the lower end of arms 23 of a mounting bracket 2d. Spacers 25 are positioned between the eyelet and the arms 23. The other ends of the arms 23 can be secured in any suitable manner as at 25 to the forward end of the gun 2. From the above description, it will be noted that the machine gun 2 by virtue of its connection to the cradle is free to have a fore and aft movement in the cradle during ring of the gun.

A support 21 for an ammunition box (not shown) is attached at its rear end to one of the bolts 5 and at its forward end by a sliding connection 28 to one of the lateral members I8.

In Figures 2 and 3, it will be observed that the gun 2 is provided with a lever 3|] which actuates the ring mechanism of the gun and a buffer 3I. A guard 32 is .provided to t over the rear section of the gun and the lever and buier 3|. In Figure 3 particularly it can be seen that a bracket 33 is mounted on the tube 9 between the handles I I and is formed with an internal groove 34. The guard 32 is provided with flanges 35 at its lower end that are adapted to slide in the grooves 36, thus enabling the -guard 32 to be moved away from the rear of the gun so that the operator may have access thereto.

The guard is further provided with a downwardly extending cup 36 having positioned therein a pin 31. The pin is provided with a limiting collar 38 and one end of coil spring 39 which is positioned around the pin bears against the collar and against a cap II!) threaded onto the cup 4 36. A button 4I is threaded onto the pin to .per-

mit easy actuation of the pin. The bottom of the guard 32 has an aperture therein and the spring 39 tends to hold normally the pin in engagement with the aperture as shown in Figure 3. To lock the guard in proper position, it is slid to the location shown in Figure 1 and the pin 31 extends into the aperture in the bottom of the guard. The spring 39 will keep the pin in this position and to slide the guard from its operative position, the operator grasps the button M and pulls the pin downwardly against the action of the spring 39. Thus the head of the pin is moved out of engagement with the aperture thereby enabling the guard to be slid to its position away from the rear of the gun.

As hereinabove pointed out, I provide a novel device for locking the firing trigger against operation. With reference to Figure 3, it will be seen that I have designated generally by the numeral 50 the firing trigger which is located adjacent the operating handles II. This trigger comprises a pair of arms 5I which are bridged at their upper ends by a thumb piece 52. The lower ends of the arms are attached to a pin 53 which extends through apertures provided in the sides of the guard 32. Locking devices 54 are attached to the ends of the pin '53 te prevent the arms from coming oi oi the pin. A pair of arms 55 are attached to the pin 53 and carry roller 55 at their free ends. In Figures l and 5 it can be seen that the outer end of the lever 30 contacts the roller 55. When the trigger 59 is moved to re the gun, the roller 55 will move the lever 39 to a substantially horizontal position thus causing the iiring of the gun.

To enable the trigger to be locked against ring, it will be observed (see Figure 4) that one of the links 55 is provided with an extension 58. A safety bar 59 slides through apertures 60 in the side walls of the guard 32 slightly above the extension 53. One of the edges of the bar 59 is formed with a cutaway portion B2 and the other edge is provided with notches 63 and 63. When it is desired to lock the trigger of the gun the bar is moved to the position shown in Figures 4 and 5 at which position the notch 63 is in alignment with a spring loaded detent 64 which extends into the notch and holds the bar in its proper position. The extension 58 bears against the underface of the bar and as a result the firing trigger cannot be moved to its operative position.

However, when it is desired to iire the gun, the safety bar is moved to the left (Figure 4) so that the detent Sli will drop into the notch 53 which will then position the cutaway portion 68 over the extension 53 thereby enabling the firing trigger to be actuated.

From the above description it is believed manifest that this very simple assembly will enable the firing mechanism of the gun to be locked and unlocked with relative ease, and the assembly by virtue of its position adjacent the operating handles will permit the operator of the gun to actuate the locking device in a minimum of time.

The recoil cylinder I 'I mentioned earlier in the description is specifically illustrated in Figures 6 to 9 inclusive. It can be seen that the cylinder comprises a chamber 10 and a second chamber 1I of lesser diameter than the chamber 19. The piston rod 20 is of such diameter as to provide a sliding fit within the chamber 1I and is formed with a longitudinal bore 12. The other end of the cylinder I1 is closed by means of plug 13. A gasket 1li is interposed between the plug and the cylinder to provide a huid-tight union. The plug is further provided with a bore 'i5 which is closed by means of a threaded bolt or the like 16 and washer 11 is positioned between the bolt head and the plug to prevent the leakage of any fluid therethrough. Fluid designated 18 is admitted into the chambers 19 and I'I through the bore 15 provided in the plug 13. When the cradle I is in a substantially horizontal plane, the fluid 'lil will asume the level shown in Figure 6.

The piston rod 20 carries a piston head 80, the diameter of which is such that the head will have a sliding movement in the chamber 10. A ball valve assembly indicated generally 8l is associated with the head Sil. The valve 3l comprises a seat 82 which is press fitted into the bore l2. A cage 83 is press fitted into the head 8b and servos to retain ball 84 in the desired positions. The cage is further provided with a ilange 85 at its outer end.

The piston head 30 is formed with a circumferential groove 8B which communicates'with the interior of the bore 'l2 of the piston rod 2i) through ports 81. A diagonal port 83 communicates at its inner end with the groove 8B and at its opposite end with an annular channel 33 provided in the piston head B between the beveled end 9B of the cage 83, and the valve seat S2. Radial slots 9| are provided in the cage and extend from the seat 82 to a point adjacent the inner face of the flange 85 to provide a passageway for the fluid 'I8 from the chamber 'l0 to the annular channel 8S, diagonal orifice 83, groove 8E, port 81, and bore 72.

A coil spring 92 is positioned in the chamber l! and one end thereof bears against the flange 85 of the cage 83 and the other end against the inner face of the plug 13. Clearly, the spring 92 will normally tend to force the piston rod 2E] forwardly.

The cylinder Il is cutaway as shown at and a packing gland 94 is positioned therein. The gland 94 will prevent any leakage of fluid from the interior of the cylinder.

In operation the recoil cylinder l functions as follows. Let us assume that the machine gun is being fired in a substantially horizontal plane. The recoil of the gun will be compensated for by the action of the spring 92 and the air which is compressed between the inner periphery of the chamber 10 and the level of the fluid 'i8 in that chamber. Consequently, the oil will have a relatively slight dampening effect, the shock of recoil being dampened mostly by the spring 92 and the column of air in the cylinder lil. However, when the cradle is moved upwardly to re at a relatively high angle (see Figure 7), the cylinder must compensate not only for the recoil of the gun, but also the added weight of the gun itself. The fluid will therefore flow back and completely ll the chamber 1U, and as it is non-compressible and permitted only to flow through the restricted orice 88, it will afford an additive dampening effect in addition to that of the spring E32, thus compensating for the recoil.

It is believed to be readily apparent from the foregoing description that I have devised a recoil cylinder which will compensate for the recoil of a machine gun regardless of the angle at which the gun is being operated. The incorporation of a fluid in the cylinder in addition to the spring will take care of the added weight of the gun in addition to the recoil when the machine gun being operated at high angles. On the other hand the spring and compression of an air column in the recoil cylinder will adequately take care of the recoil when the gun is firing at those angles at which we do not have to take care of the additional weight of the gun. The unit relatively simple in construction and operation and the interior is readily accessible in the event it becomes necessary to repair or replace any of the working parts.

While I have shown and described the preferred embodiment of my invention, I Wish it to be understood that I do not confine myself to the precise details of construction herein set forth by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. In a construction for dampening the recoil of a machine gun, a cylinder having a chamber open at one end toward the forward end of the gun, a piston rod slidable in said open end oi the cylinder, means closing the other end of the chamber, a head carried by the piston rod and reciprocable in the chamber, a recoil spring within the chamber to dampen the longitudinal recoil movement of the piston rod when the cylinder is in a substantially horizontal plane, a bore in the piston rod, said piston having a passage therethrough communicating with said bore, a valve chamber in the passage in the piston head, a check valve in said valve chamber, liquid partially filling the bore of the piston rod and the chamber When the cylinder is in a substantially horizontal plane, and a restricted by-pass passage in the piston head providing communication between the valve chamber and piston rod bore, said check valve being constructed and arranged to open upon flow of liquid from the bore into the chamber for the free flow of liquid from the bore into the chamber upon inclination of the cylinder to bring the chamber to a level below that of the piston rod bore, and to close upon flow of liquid in the opposite direction, whereby resistance to displacement of the piston toward the closed end of the chamber, in addition to that of the spring, when the cylinder is substantially horizontal is effected by compression of the air above the liquid level and when the cylinder is inclined and the chamber is filled with liquid the resistance is effected by the restricted flow of liquid through said bypass.

2. In a construction for dampening the recoil of a machine gun, a cylinder having a chamber open at an end toward the forward end of the gun, a piston rod slidable in said open end and formed with a bore therein, means closing the other enol of said chamber, a head carried by the piston rod and reciprocable in said chamber, a liquid partially filling the bore in the piston rod and the chamber when the cylinder is in a substantially horizontal plane, said piston having a passage therethrough communicating with said bore, a valve chamber in the passageway in the piston head, a check valve body in said valve chamber adapted to close upon fiow of liquid into the piston rod bore, a cage in said valve chamber for retaining said valve in position, a circumferential groove in the piston head communicating with the bore in the piston rod through radial ports, a restricted by-pass extending between said circumferential groove and an annular channel in the valve chamber, and slots in said cage for the flow of liquid about said valve body, said check valve being constructed and arranged to open upon flow of liquid from the bore into the chamber for the free flow of liquid from the bore into the chamber upon inclination of the cylinder to bring the chamber to a level below that of the piston rod bore, and to close upon now of liquid in the opposite direction, whereby resistance to displacement of the piston toward the closed end of the chamber when the cylinder is substantially horizontal is eifected by compression of the air above the liquid level and when the cylinder is inclined and the chamber is lled with liquid the resistance is effected by the restricted flow of liquid through said by-pass.

3. A recoil dampener for machine guns comprising a cylinder closed at one end, means construoted and arranged for attaching said cylinder to a machine gun with its axis substantially parallel to the gun axis and movable through angles of elevation therewith, a piston in said cylinder, a piston rod carried by said piston and extending through the other end of said cylinder in a direction forwardly of the gun, said piston having a flow passage extending therethrough, a check valve in said passage mounted for closing upon displacement of the piston toward the closed end of the cylinder, said piston having a second passage 'by-passing said check` valve, said by-pass passage being positioned in the upper portion of said piston, a body of liquid in said cylinder suflicient to i'lll the same when the gun is moved through an angle of elevation to raise its forward end, and a reservoir communicating with the end of the cylinder through which the piston rod extends and positioned to drain liquid from the cylinder to a level below the bypass passage when the cylinder is in a substantially horizontal position.

4. A recoil dampener for machine guns comprising a cylinder closed at one end, means constructed and arranged for attaching said cylinder to a machine gun with its axis substantially parallel to the gun axis and movable through angles of elevation therewith, a piston in said cylinder, a piston rod carried by said piston and extending through the other end of said cylinder in a direction forwardly of the gun, said piston having a flow passage extending therethrough, a check valve in said passage mounted for closing upon displacement of the piston toward the closed end of the cylinder, said piston having a second passage by-passing said check valve, said by-pass pasage being positioned in the upper portion of said piston, a body of liquid in said cylinder sufficient to fill the same when the gun is moved through an angle of elevation to raise its forward end, a reservoir communicating with the end of the cylinder through which the piston rod extends and positioned to drain liquid from the cylinder to a level below the by-pass passage when the cylinder is in a substantially horizontal position, and a recoil spring in said cylinder urging said piston away from the closed end.

JOHN C. TROTTER. 

